Biomedical subjects

S Sánchez-Suero

Publications and source records attributed to S Sánchez-Suero.

5 recordsLinked to original sources

PubMed1994

Visual evoked potentials in response to pattern reversal in the cat cortex.

A model of the visually evoked potential (VEP) in the cerebral cortex of the cat after binocular stimulation by means of pattern reversal is presented. The VEP is defined by four components: P1, N1, P2 and N2, which appear during the 100 ms following the stimulus. This model is repeated for the majority of recording points although N1 and P2 do not appear to be homogeneous over the entire cortex. The variability of the VEPs recorded at the same point in different cats is lower than the one observed by means of stimulation with flashes. The possible origin of the four components in the primary visual area is presented as a hypothesis and a discussion is made of the differences which exist between the models proposed for flash and pattern reversal.

Animals↗

PubMed1994

Visual evoked potentials in response to flashes in the cat cortex.

A model is presented of visually evoked potentials (VEPs) in the cerebral cortex of cats after binocular stimulation by means of flashes. The VEPs consist of four components: P1, N1, P2 and N2 which appear during the first 100 ms after the stimulation is produced. This model has been found in all the animals used in the experiments and is repeated with small variations at almost all the recording points. After studying the data obtained, a hypothesis is put forward for the possible origin of the four components in the primary visual area.

Animals↗

PubMed1994

Effect of stimulus intensity on visually-evoked electrical brain activity maps in rabbit.

Stimulation by means of flashes is a commonly-used method in basic research into evoked potentials. Nevertheless, the different responses obtained at different luminous intensities, to which the inter-individual and intra-individual differences are added, determine the need to control this stimulus parameter for each experimental model. Maps of visually-evoked activity in the rabbit brain, obtained after monocular stimulation with flashes at different intensities of luminosity, are presented. Variation in the intensity of the luminous stimulus does not substantially affect the distribution of the electrical potential on the surface of rabbit brain described in previous articles.

Animals↗

PubMed1993

[Maps of visually evoked brain electrical activity in rabbits].

A basic model of topographic distribution of the electric response visually evoked in rabbits by means of flashes (0.69 joules/flash) has been obtained. The model is composed of four main parts--N0, P1, N1 y P2--linked to the VI visual area and displayed on a dipole shaped. The dipole turnaround time oscillates between 20 and 25 ms. The use of electrical activity brain maps on the study of the PE makes it possible to notice the phenomenon simultaneousness, thus facilitating its interpretation. A multinomial interpolation method of continuous function has been used to perform the maps.

Animals↗

PubMed1993

[Brain potential mapping by a new method of polynomial interpolation].

The mapping of evoked cerebral activity is largely determined by the choice of the interpolation system used. When the number of electrodes is very large, practically any interpolation system is valid, but the geometrical and anatomical limitations imposed by the animals normally chosen for these experiments impede the use of a large number of electrodes; hence the overriding importance of a workable interpolation system. The polynomic interpolation method on the monomial structure is presented as valid, and compared with the pseudolineal interpolation method, which is more commonly used.

Algorithms↗